Even as gay rights groups cheered New York's adoption of same-sex marriage last month, their opponents called the vote an isolated setback and started planning how to use the specter of New York to rally their troops and fill their coffers for the battles ahead.

Less than 24 hours after the New York Senate's vote, made possible by four Republican defections, a leading anti-same-sex-marriage group started sending out defiant pleas for money.

"This fight is far from over," the National Organization for Marriage told supporters as it pledged to spend $2 million in 2012 to defeat New York's four "turncoat senators" who "betrayed marriage."

The organization, which says it expects to raise $20 million this year from Roman Catholic and evangelical Christian groups as well as individual donors, is gearing up for intense battles over same-sex marriage in several other states. So far, voters in 29 states have adopted constitutional amendments banning it.

Since the vote, the Family Research Council, one of the largest conservative Christian advocacy groups, started hearing from more followers who wanted to defend traditional marriage, and officials said they expected a jump in donations.

"More than ever before, people are seeing this as a national issue," said Tom McClusky, senior vice president of the council.

National and state organizations fighting same-sex marriage have raised millions of dollars on the issue in recent years and won some major victories, including the unseating last fall of three Iowa Supreme Court justices who had ruled against marriage restrictions. But some say their fundraising has sometimes been impeded by the harassment of donors, an accusation that gay rights groups call exaggerated.

In Minnesota, where both sides are preparing for a vote next year on a constitutional amendment to outlaw same-sex marriage, conservatives are fighting financial disclosure requirements that they say would expose donors to intimidation.

"If gay marriage supporters think that New York is an indication of a national trend, they are mistaken," said Brian Brown, the president of the National Organization for Marriage, which has received large donations from the Knights of Columbus, the Roman Catholic fraternal organization.

A battle is expected soon in Maine, where gay rights proponents, inspired by the outcome in New York, announced last week that they would start gathering signatures to put same-sex marriage on the ballot next year. The governor signed into law in 2009 a bill allowing same-sex marriage, but opponents pushed it to a referendum, and voters defeated it a few months later.

North Carolina will be another early battleground, with its legislature, now controlled by Republicans, expected to consider this fall whether to put a constitutional amendment banning same-sex marriage before voters in November 2012. North Carolina is the only state in the Southeast without such an amendment.

Another battle is expected in New Hampshire, one of the states that has adopted same-sex marriage. Pressure is mounting for the legislature to take another historic step by reversing course.

In Maryland, a last-minute push by opponents this spring derailed a same-sex-marriage law that had been widely expected to pass. Buoyed by New York, gay rights advocates plan to press for a vote to reverse that outcome next year.

But opponents say that even if the measure passes the legislature, they will gather signatures to force a "people's referendum."